Which freqs should be scanned in Motorola Type II system?

[DanRichman]

Please forgive me if this is a FAQ (which it seems it should be, because it's so basic), but I haven't seen the answer anywhere.

Various sources (such as files submitted by other scanner enthusiasts, Web postings, books) list varying numbers of frequencies for a given Motorola Type II system. Presumably, all of those should be scanned.

Yet other sources say to scan only the control frequencies.

Isn't it true that the more freqs scanned, the slower the scanning? Therefore, wouldn't we want as few freqs to be scanned as possible?

If the answers to those are both "yes," then which freqs should be entered in a given system? Is there some consistent, reliable way to determine this?

Thanks in advance.

 

[RolnCode3]

It depends on what type of/which scanner you have. Some need ONLY the control channels. Some need only the control channels, but you have to figure out what "Plan" the system is using. Presumably, other scanner require all of the channels (I don't own any like that). That's why different files list different numbers of freqs.

As for being slower, if you're talking about 4 freqs vs. 28 freqs, it really isn't that big of a deal. Some scanners might even skip other trunked freqs if they've already found a control channel (the BC785 will only follow one CC per bank, but I don't know how it thinks). I have heard to put the CCs at the beginning of a bank, but it's not mandatory.

 

[JoeyC]

In trunking, frequencies are not scanned.

Depending on your trunk scanner, you may only need to program the control freqs.

 

[DanRichman]

Thanks, guys, for your responses.

To RolnCode3: I thought plans are not used with Motorola Type II systems. Am I wrong?

To JoeyC: So why should I list anything but the control channel? And why would there be more than one?

I'm using the BC246T scanner, which (as I remember) offers the option of scanning only the control channel. Which raises raises more questions than it answers, among them:

-Why should I enter any other channels if only the control channel matters?

-What is the effect in the scanner's speed or efficiency of checking (or leaving unchecked) that box?

 

[RolnCode3]

Some of the Unidens (my 785 for example) has some screwy setup based on the frequencies, where you have to help the scanner figure out how the system works. It uses "plans" that are unique to the scanners...nothing to do with the actual system. It's not like a fleetmap for the TypeI systems.

 

[JoeyC]

With the 246 you only need to program control channels. You do not need to program the others. The control channel carries all the info the scanner needs to monitor the system and will listen to the appropriate frequency when the control channel tells it to (based on which talkgroup is active)

Not sure what box you are referring to regarding the speed. Whatever, the speed difference will be negligable, and probably not a difference at all.

 

[DanRichman]

OK, JoeyC: Assuming you're right (and I have no reason to doubt it), is the way to establish which channels are control channels simply by listening for the distinctive noise?

And having found all the CCs for a system -- presumably there's more than one? -- one can ignore the other frequencies used on it? (I guess this just applies to the BC246T.)

 

[JoeyC]

Yep, just listen for the buzzsaw. Or, lookup the system on the database here. There can be from 1-4 controls. Only one is used at a time, and they may alternate or they may not.

Ignoring the other system freqs is not exclusive to the 246, but for any scanner that does control channel only trunking...

 

[DanRichman]

Thanks again, JoeyC. I'll let you know how this works out.

 

[DanRichman]

oops! another question--if all that's required are the control channels, why are many, many more channels listed for the system in this web site's database? (i'm referring to the seattle/king county system.)

 

[loumaag]

oops! another question--if all that's required are the control channels, why are many, many more channels listed for the system in this web site's database? (i'm referring to the seattle/king county system.)

Not all scanners have that capability. Some require that all the frequencies be entered. Also, you will note that it seems only one frequency is listed at each site as the CC. While it is true that only one can be the CC at any time, there is an alternate, and if it is not marked, you might want to try and figure out what it is when your radio suddenly quits working. :wink:

 

[WX5JCH]

don't forget to activate the control channel option in your 246's settings or it won't work for you.

 

[DanRichman]

skywatch, could you elaborate on your point? precisely how do i make that setting?

during today's drive, i locked out a bunch of (what i thought were) talk groups, and now i can't get a single peep out of the trunked systems i've programmed, even though i went through and unlocked everything. i'm at a loss.

 

[DanRichman]

never mind, skywatch--i didn't realize i had my manual with me, and having checked it, i now understand what you meant. that has fixed the problem.

but why it worked this morning, and then stopped working, i can't figure.

when i programmed the radio last night (using the beta version of the dutch software, whatever it's called), i don't think there was a provision for this choice, called Control-Channel Only. so it must have been in its default position, which is OFF.

but the position i required is ON.

so what happened? did i maybe do some combination of key presses that altered this setting?

we may never know . . .

 

[W4KRR]

never mind, skywatch--i didn't realize i had my manual with me, and having checked it, i now understand what you meant. that has fixed the problem.

but why it worked this morning, and then stopped working, i can't figure.

Sounds like maybe the control channel changed to a frequency that you don't have programmed in.

 

[DanRichman]

ah, that could be.

i clearly have much to learn.

thanks for your help.

 

[DanRichman]

does the order in which the control freqs appear affect the speed of the scanner? i.e., should those freqs that are closest to me when i'm using the scanner be listed first?